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Detection of Horizontal Gene Transfer Mediated by Natural Conjugative Plasmids in E. coli
Published on: March 24, 2023
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Plasmids Shaped the Recent Emergence of the Major Nosocomial Pathogen Enterococcus faecium
S Arredondo-Alonso1, J Top1, A McNally2
1Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands.
Mbio
|February 13, 2020
Summary
This study analyzed the plasmidome of 1,644 Enterococcus faecium isolates, revealing that plasmids, not chromosomes, are key to identifying infection sources. Hospitalized patients
Area of Science:
- Microbiology
- Genomics
- Molecular Biology
Background:
- Enterococcus faecium is a significant cause of hospital-acquired infections and is a priority pathogen due to multidrug resistance.
- Antibiotic resistance genes in E. faecium are often located on plasmids, facilitating their spread via horizontal gene transfer.
- Understanding the complete plasmid content (plasmidome) is crucial for tracking the evolution and spread of antibiotic resistance.
Purpose of the Study:
- To conduct a comprehensive population-wide analysis of the pan-plasmidome of Enterococcus faecium.
- To investigate the role of plasmids in the adaptation and source specificity of E. faecium.
- To identify mechanisms of plasmid stabilization and their association with specific E. faecium populations.
Main Methods:
- Whole-genome sequencing of 1,644 E. faecium isolates from diverse sources (hospital, commensal, animal).
- Long-read sequencing for plasmid reconstruction and characterization.
- Short-read sequencing combined with machine-learning classifiers to determine the complete plasmidome.
Main Results:
- Identified distinct E. faecium populations associated with hospitalized patients, suggesting adaptation to the hospital environment.
- Characterized plasmid modularity and identified common plasmid stabilization mechanisms like toxin-antitoxin systems.
- Discovered specific genes (e.g., copper resistance, phosphotransferase systems, bacteriocins) enriched in certain plasmidome populations.
- Demonstrated that plasmidomes, rather than chromosomes, are more informative for determining the source of E. faecium isolates.
Conclusions:
- Plasmidome composition is a strong indicator of E. faecium source and adaptation.
- Mechanisms like toxin-antitoxin systems contribute to plasmid stability and persistence.
- Ecological constraints, rather than direct host interaction, likely drive plasmid dynamics in E. faecium populations.
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